The "unprecedented success" of the BNP Butchers keeps on about is of course on the back of media hysteria, a gutless Labour government, leading to the collapse of the Labour vote and voter apathy generally.
The BNP's tactic, if it ever had one, has been mainly standing in elections and scooping up the rewards of all this. The left, leaving out the media hysteria, has attempted to do similar, SP, Respect, SLP, Left List and whilst there's been some success, most have not been able to match the BNP in electoral terms, apart from the Green Party, who have and more so.
If we switch to your favourite pet subject, class, I don't see a great impact in working class areas, certainly not on the same scale as the NF had at it's height. As I see it, Barnsley, Stoke, Barking and Dagenham are not about to succumb to BNP incompetence any time soon.
There have also been setbacks for the BNP, in Burnley, Oldham, Sandwell and in parts of Yorkshire, so not the "unprecedented success" they were expecting. The two seats in the European elections were the life boat for the leadership. No guarantee they'll see land, never mind take over institutions
I'm not certain how this will play out, but recent elections suggests the BNP vote is now falling. Not sure if that will be a permanent feature? So no room for complacency here.
Important to understand that the tactical choices available to the BNP now are limited. No more stunts, it's all about electoral respectability and beavering away at the institutions for them. Let's be clear, their organisational structure is weak and they are nowhere near becoming a mass party.